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Intelligent lighting for the 21st century | Part 3

DEFECTS IN AUTOMOTIVE PANELS >

From aesthetics to performance,

we can help to ensure quality.

Pixel size and well capacity

The sensors found in cameras used for vision
applications have pixels that convert
incoming photons into electrons.

The
electrons are held in each pixel and are
converted into electrical charge which
can be measured to show the amount
of light that has fallen on each pixel. The
maximum electrical charge possible is termed "full well capacity". The
greater the full well capacity the greater the dynamic range, assuming
other influencing factors such as noise and A/D converter quality are
equal. As there is a limit to the depth to which pixels can be made, the
full well capacity is often proportional to the frontal area of the light
gathering element of the pixel.

The fill factor is the measure of the area
of the pixel that can gather light. Some sensors with a frame transfer or
full frame architec ture boast 100 % fill factor as the entire pixel is
photosensitive. Interline transfer CCDs or CMOS sensors may only have
a 20-50 % fill factor as much of the pixel is occupied with read-out or
charge conversion and digitisation structures. Microlenses are
sometimes used with this type of sensor being placed over each pixel to
guide the light from a wider area onto the photosensitive area.